Indications
Nitroglycerin sublingual tablet is indicated for the acute relief of an attack or acute prophylaxis of angina pectoris due to coronary artery disease.
Pharmacology
Nitroglycerin forms free radical nitric oxide (NO) which activates guanylate cyclase, resulting in an increase of guanosine 3'5' monophosphate in smooth muscle and other tissues. These events lead to dephosphorylation of myosin light chains, which regulate the contractile state in smooth muscle and result in vasodilatation.
Dosage And Administration
One sublingual tablet should be dissolved under the tongue at the first sign of an acute anginal attack. The dose may be repeated approximately every five minutes, until relief is obtained. If the pain persists after a total of 3 tablets in a 15-minute period, prompt medical attention is recommended.
Interaction
Patients receiving antihypertensive drugs, beta-adrenergic blockers or phenothiazines and nitrates should be observed for possible additive hypotensive effects. Marked orthostatic hypotension has been reported when calcium channel blockers and organic nitrates were used concomitantly. Concomitant use of nitrates and alcohol may cause hypotension. The vasodilatory and hemodynamic effects of Nitroglycerin may be enhanced by concomitant administration of aspirin. Patients receiving sublingual Nitroglycerin should avoid ergotamine and related drugs or be monitored for symptoms of ergotism if this is not possible.
Contraindications
Sublingual Nitroglycerin therapy is contraindicated in patients with early myocardial infarction, severe anemia, increased intracranial pressure and those with a known hypersensitivity to Nitroglycerin. Administration of Nitroglycerin is contraindicated in patients who are using sildenafil citrate since sildenafil citrate has been shown to potentiate the hypotensive effects of organic nitrates.
Side Effects
Headache which may be severe and persistent may occur immediately after use. Vertigo, dizziness, weakness, palpitation and other manifestations of postural hypotension may develop occasionally.
Pregnancy And Lactation
Nitroglycerin should be given to a pregnant woman only if clearly needed. It is not known whether Nitroglycerin is excreted in human milk.
Precautions And Warnings
Only the smallest dose required for effective control of the acute anginal attack should be used. Excessive use may lead to the development of tolerance. This drug should be used with caution in patients who may be volume-depleted or are alredy hypotensive.
Therapeutic Class
Nitrates: Coronary vasodilators
Storage Conditions
Store in a cool and dry place away from light and heat. Keep all medicines out of the reach of children.